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Question 1341
StructuredStandard4 marks
CBSE Class 11 Mathematics · Trigonometric Functions · Compound-angle identities

Prove \(\dfrac{\tan(\frac\pi4+x)}{\tan(\frac\pi4-x)}=\left(\dfrac{1+\tan x}{1-\tan x}\right)^2\).

Question 1342
StructuredStandard3 marks
CBSE Class 11 Mathematics · Relations and Functions · Functions and their graphs

Let \(f=\{(ab,a+b):a,b\in\mathbb Z\}\). Is this a function from \(\mathbb Z\) to \(\mathbb Z\)? Justify.

Question 1343
StructuredStandard5 marks
CBSE Class 11 Chemistry · Organic Chemistry: Some Basic Principles and Techniques · Quantitative analysis and applications

A \(0.468\,\mathrm{g}\) sulfur compound gives \(0.668\,\mathrm{g}\) BaSO₄ by Carius analysis. Determine its sulfur percentage.

Question 1344
StructuredStandard5 marks
CBSE Class 11 Chemistry · Equilibrium · Acid-base equilibria and pH

Determine meant by the conjugate acid-base pair? Find the conjugate acid/base for the following species: HNO2, CN–, HClO4, F –, OH–, CO , and S2–

Question 1345
StructuredStandard3 marks
CBSE Class 11 Chemistry · Chemical Bonding and Molecular Structure · Valence-bond and molecular-orbital theories

Use molecular-orbital theory to explain why Be₂ is not stable.

Question 1346
McqStandard2 marks
CBSE Class 11 Chemistry · Classification of Elements and Periodicity in Properties · Periodic classification and electronic configuration

Which listed factor does not materially affect the valence shell: valence n, nuclear charge, nuclear mass, or core-electron count?

Question 1347
StructuredStandard3 marks
CBSE Class 11 Chemistry · Structure of Atom · Subatomic particles and atomic symbols

A carbon atom has diameter 0.15 nm. How many such atoms fit side by side along \(20\,\mathrm{cm}\)?

Question 1348
StructuredStandard4 marks
CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Stoichiometry and limiting reagents

Calcium carbonate reacts as CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O. What mass of CaCO₃ reacts completely with 25.0 mL of 0.750 M HCl?

Question 1349
StructuredStandard3 marks
CBSE Class 11 Mathematics · Relations and Functions · Functions and their graphs

Let \(f=\{(ab,a+b):a,b\in\mathbb Z\}\). Is this a function from \(\mathbb Z\) to \(\mathbb Z\)? Justify.

Question 1350
StructuredStandard6 marks
CBSE Class 11 Mathematics · Sets · Complement and set identities

Taking \(\mathbb N\) as universal set, describe the complements of:

(a)
even numbers
(b)
odd numbers
(c)
positive multiples of 3
(d)
primes
(e)
multiples of both 3 and 5
(f)
perfect squares
(g)
perfect cubes
(h)
solutions of \(x+5=8\)
(i)
solutions of \(2x+5=9\)
(j)
numbers \(x\ge7\)
(k)
numbers satisfying \(2x+1>10\).